1. Field of the Invention
The present invention relates to magnetic bearings, and more specifically, it relates to techniques for electrostatically stabilizing magnetic bearings.
2. Description of Related Art
Passive magnetic bearing systems such as those described in U.S. Pat. No. 5,495,221, “Dynamically Stable Magnetic Bearing System” consist of two basic elements: (1) Levitating magnets, and (2) a “stabilizer element” such as the stabilizers described in U.S. Pat. No. 5,847,480, “Passive Magnetic Bearing Element with Minimal Losses,” incorporated herein by reference. The stabilizers are required as a consequence of Earnshaw's Theorem which proves that no stationary configuration of permanent magnets can magnetically levitate another permanent magnet system and maintain it in static equilibrium. The way around the strictures of Earnshaw's Theorem is to employ dynamic effects to achieve stability. In the cited patent, the stabilizers described employ rotating annular Halbach arrays to induce currents in stationary windings when the rotating system moves away from its intended levitated equilibrium position. These stabilizers thus are based on the use of electromagnetic fields and forces and thus necessarily involve some level of conduction and eddy-current losses. Stabilizers based on the use of electrostatic forces and involving near-zero internal losses are desirable.